Milbemycin Oxime (Interceptor®) for Dogs and Cats

Milbemycin Oxime (Interceptor®) for Dogs and Cats

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Overview of Milbemycin Oxime (Interceptor®) for Dogs and Cats

  •  Milbemycin Oxime, also known as Interceptor®, is used to control hookworm, roundworm, and certain whipworm infections in dogs and cats. Milbemycin is commonly combined with other drugs to create a variety of prevention medications. For example, Milbemycin with Lufenuron is Sentinel®, and Milbemycin with Spinosad is Trifexis®. 
  • Parasitic infections are common in dogs and cats and include external parasites (fleas, ticks, mites), and internal parasites (intestinal worms, lungworms and heartworms).
  • Milbemycin oxime is a parasite control drug effective in controlling or preventing several of the most common parasitic diseases of dogs and cats. It is commonly used to prevent heartworms and control disease caused by roundworms, hookworms in dogs and cats and certain whipworms in dogs.
  • Milbemycin acts by disrupting nerve transmission within the parasite leading to death of the parasite.
  • Milbemycin has been found safe in collie breeds and in collie mixed breeds.
  • Milbemycin is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
  • Brand Names and Other Names of Milbemycin Oxime

  • This drug is registered for use in animals only.
  • Human formulations: None
  • Veterinary formulations: Interceptor® (Novartis Animal Health) Milbemycin is also available in combination with praziquantel as Milbemax®
  • Uses of Milbemycin for Dogs and Cats

  • Milbemycin is used to control hookworm, roundworm, and certain whipworm infections in dogs and cats. The drug is also a highly effective preventative of canine heartworm disease and feline heartworm disease.
  • Veterinarians use milbemycin in an extra-label manner to treat and control demodectic mange infections.
  • Milbemycin is a potent microfilariacidal drug, meaning it can kill the microscopic offspring of heartworms. Microfilaria circulate in the blood of infected dogs and are typically treated after killing the adult heartworm parasite with another drug (melarsamine). Milbemycin is one of the drugs veterinarians use to kill the microfilaria as there are no drugs approved for this use by the FDA. This represents another extra-label use of this drug.
  • Precautions and Side Effects

  • While generally safe and effective when prescribed by a veterinarian, milbemycin can cause side effects in some animals.
  • Milbemycin should not be used in animals with known hypersensitivity or allergy to the drug.
  • Animals should be tested for heartworm infection before beginning prevention with milbemycin.
  • Milbemycin should not be used in puppies under 4 weeks of age or kittens under 6 weeks of age. It should also not be used in dogs weighing less than 2 pounds or cats weighing less than 1.5 pounds.
  • Few adverse effects have been reported.
  • There have been a few unconfirmed reports of seizures and nervous system effects following milbemycin administration.
  • When used in an extra-label manner to kill heartworm microfilaria, the dog should be carefully observed for a shock-like reaction that may occur following administration. This generally involves hospitalizing the dog for the day of treatment so that supportive care can be administered if needed. This same shock-like reaction can be observed if milbemycin is administered as a heartworm preventative to a dog or cat harboring a mature heartworm infection.
  • How Milbemycin Is Supplied

  • Milbemycin is available in 2.3 mg, 5.75 mg, 11.5 mg and 23 mg tablets.
  • Dosing Information of Milbemycin Oxime for Dogs and Cats

  • Medication should never be administered without first consulting your veterinarian.
  • For control of parasites other than Demodex spp, the canine dose of milbemycin is at least 0.23 mg per pound (0.5 mg/kg) once monthly. For cats, the dose is at least 0.9 mg per pound (2 mg/kg) once monthly.
  • For control of the demodectic mange mite in dogs, milbemycin is dosed at 0.25 to 0.5 mg per pound (0.5 to 1 mg/kg) daily for 90 days.
  • For killing of heartworm microfilaria in dogs, the drug is usually given as a single dose of 0.25 mg per pound (0.5 mg/kg), with the treatment administered while the dog is observed at a veterinary hospital.
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.
  • Note: This information is provided by veterinarians. For official prescribing information for this drug, read the article “Interceptor®.”
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    Anti-Parasitic Drugs (Heartworms)
    Anti-Parasitic Drugs (Gastrointestinal & Internal)



    Cardiology & Cardiovascular diseases
    Gastroenterology & Digestive diseases


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